Initial implementation of WorkletAnimation

third_party/WebKit/Source/modules/compositorworker/WorkletAnimation.h

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef WorkletAnimation_h
+#define WorkletAnimation_h
+
+#include "bindings/core/v8/serialization/SerializedScriptValue.h"
+#include "bindings/modules/v8/document_timeline_or_scroll_timeline.h"
+#include "core/animation/Animation.h"
+#include "core/animation/KeyframeEffectReadOnly.h"
+#include "core/animation/WorkletAnimationBase.h"
+#include "modules/ModulesExport.h"
+#include "platform/animation/CompositorAnimationDelegate.h"
+#include "platform/animation/CompositorAnimationPlayer.h"
+#include "platform/animation/CompositorAnimationPlayerClient.h"
+#include "platform/bindings/ScriptWrappable.h"
+
+namespace blink {
+
+class MODULES_EXPORT WorkletAnimation : public WorkletAnimationBase,

[nhiroki, 2017/09/08 03:58:22]

Can you add class-level comments? Which thread does this lives on?

Worker/Worklet components are heavily threaded, so comments about thread model
and checks like DCHECK(IsMainThread()) at the beginning of each public function
would be really helpful for code readers.

[smcgruer, 2017/09/11 18:19:00]

Added some comments + DCHECKS, let me know if they answer your questions.

+                                        public ScriptWrappable,
+                                        public CompositorAnimationPlayerClient,
+                                        public CompositorAnimationDelegate {
+  DEFINE_WRAPPERTYPEINFO();
+  USING_PRE_FINALIZER(WorkletAnimation, Dispose);

[haraken, 2017/09/08 01:11:23]

Would you help me understand why you need to call Dispose in a pre-finalizer?

In general it's not encouraged to do complex operations in a pre-finalizer. Is
there any other explicit point where you can call Dispose()?

[smcgruer, 2017/09/11 18:19:00]

My understanding is that you cannot access any heap member during your
destructor (correct?). Based on that understanding, how else would one remove a
WorkletAnimation object from the CompositorTimeline when the last reference to
the object goes away? (Which, one day, will only happen when the user script
holds no references to the WorkletAnimation *and* when the animation subsystem
is done with it.).

+
+ public:
+  static WorkletAnimation* Create(
+      String animator_name,
+      const HeapVector<Member<KeyframeEffectReadOnly>>&,
+      HeapVector<DocumentTimelineOrScrollTimeline>&,
+      RefPtr<SerializedScriptValue>,
+      ExceptionState&);
+
+  virtual ~WorkletAnimation() {}
+
+  String playState();
+  void play();
+  void cancel();
+
+  // WorkletAnimationBase implementation.
+  bool StartOnCompositor() override;
+
+  // CompositorAnimationPlayerClient implementation.
+  CompositorAnimationPlayer* CompositorPlayer() const override {
+    return compositor_player_.get();
+  }
+
+  // CompositorAnimationDelegate implementation.
+  void NotifyAnimationStarted(double monotonic_time, int group) override {}
+  void NotifyAnimationFinished(double monotonic_time, int group) override {}
+  void NotifyAnimationAborted(double monotonic_time, int group) override {}
+
+  void Dispose();
+
+  String Name() { return animator_name_; }
+
+  const HeapVector<DocumentTimelineOrScrollTimeline>& Timelines() {
+    return timelines_;
+  }
+
+  const RefPtr<SerializedScriptValue> Options() { return options_; }
+
+  DECLARE_VIRTUAL_TRACE();
+
+ private:
+  WorkletAnimation(String animator_name,
+                   Document&,
+                   const HeapVector<Member<KeyframeEffectReadOnly>>&,
+                   HeapVector<DocumentTimelineOrScrollTimeline>&,
+                   RefPtr<SerializedScriptValue>);
+
+  String animator_name_;

[nhiroki, 2017/09/08 03:58:22]

const?

[smcgruer, 2017/09/11 18:19:00]

Done.

+  Animation::AnimationPlayState play_state_;
+
+  Member<Document> document_;
+
+  HeapVector<Member<KeyframeEffectReadOnly>> effects_;
+  HeapVector<DocumentTimelineOrScrollTimeline> timelines_;
+  RefPtr<SerializedScriptValue> options_;
+
+  std::unique_ptr<CompositorAnimationPlayer> compositor_player_;
+};
+
+}  // namespace blink
+
+#endif